Vishal Mahajan

An outbreak of acute Trypanosoma evansi infection in crossbred cattle in Punjab, India

An outbreak of acute trypanosomosis caused by Trypanosoma evansi in Punjab, a northern state of India was investigated in a cattle farm comprising 78 adults (lactating and dry) and 27 calves. The outbreak in the affected animals exhibiting high fever (105°F), circling, tremors, convulsions and death within 24–48 hours was confirmed based on examination of Wright-Giemsa stained blood smears, morpho-metric measurements and by polymerase chain reaction by using T. evansi specific primers yielding species specific 227 bp PCR product. Pretreatment parasitaemia estimated in three clinical cases revealed 12.5×104, 11.2×104 and 16.7×104 tryps/µl of blood and cow that was treated with isometamedium chloride revealed parasitemia of 1.4×104 tryps/µl of blood 24 hours after treatment while no parasitemia was found after 24 hrs of treatment in other two cows, treated with quinapyramine sulphate and chloride combination (Triquin). Post-mortem revealed moderate enlargement of spleen. Biochemical parameters revealed increase in cholesterol, bilirubin and total proteins.

Evaluation of factors contributing to excessive nitrate accumulation in fodder crops leading to Ill-health in dairy animals

A study was conducted to estimate nitrate content in commonly used fodder crops, viz., berseem (Trifolium alexandrinum), bajra (Pennisetum glaucum), maize (Zea mays), oats (Avena sativa), sorghum (Sorghum vulgare) and toriya (Brassica napus), collected from the fields of different villages of Punjab and farms of the university, and to evaluate the factors associated with nitrate accumulation in these crops. The nitrate level was highest in sorghum on dry matter basis, followed by oats and toriya, berseem, maize and bajra. The nitrate content was also determined in fodder samples harvested from young and mature stages and in different parts of plants. The stem part of forages had higher content than leaves; however, concentrations were low in mature crops as compared to immature ones. The environmental and soil factors associated with it are discussed and correlated with the experimental findings.

Detection of Mycobacterium tuberculosis and Mycobacterium bovis in Sahiwal cattle from an organized farm using ante-mortem techniques.

Aim: The aim of this study was to investigate the prevalence of bovine tuberculosis (TB) and detection of Mycobacterium bovis in cattle from an organized dairy farm. Materials and Methods: A total of 121 animals (93 females and 28 males) of 1 year and above were studied for the prevalence of bovine TB using single intradermal comparative cervical tuberculin (SICCT) test, bovine gamma-interferon (γ-IFN) enzyme immunoassay, and polymerase chain reactions (PCRs). Results: Out of total 121 animals, 17 (14.04%) animals were positive reactors to SICCT test while only one (0.82%) animal for γ-IFN assay. By PCR, Mycobacterium TB complex was detected in 19 (15.70%) animals out of which 4 (3.30%) animal were also positive for M. bovis. Conclusions: Diagnosis of bovine TB can be done in early stage in live animals with multiple approaches like skin test followed by a molecular technique like PCR which showed promising results.

Histopathological and immunohistochemical approaches for the diagnosis of Pasteurellosis in swine population of Punjab.

Aim: Infectious porcine bronchopneumonia, caused by Pasteurella multocida, is a widespread disease of major economic significance. Thus, the aim of the present study was to diagnose swine Pasteurellosis using gross, histopathological, and immunopathological approaches in the swine population of Punjab and to compare the efficacy of immunohistochemical (IHC) techniques with conventional diagnostic techniques. Materials and Methods: A total of 71 adult swine lung samples showing gross pneumonic changes were collected along with the associated lymph nodes to carry out the study. The collected samples were then processed for histopathological and IHC studies. Results: Out of the total 71 lung samples, 26 samples were found to be suspected for Pasteurellosis as per the microscopic changes observed, and out of these 26 samples, 16 cases were confirmed to be positive for Pasteurellosis by IHC. Varied macroscopic changes noted in lungs were pneumonic patches with consolidation of many lobes, congestion, and focal hemorrhages. Main lesions associated with lymph nodes were its enlargement and hemorrhages. Histologically, the lung showed fibrinous and suppurative bronchopneumonia, multifocal suppuration, thickening of septa with fibrin combined with cellular infiltration and edema. The higher IHC expression of P. multocida was seen in the bronchial epithelium besides in alveolar and bronchial exudate. Moreover, on comparing the histopathological and IHC scores which were calculated on the basis of characteristic microscopic lesions and number of antigen positive cells, respectively, a significant positive correlation (r=0.4234) was found. Conclusion: It was concluded that swine population of Punjab is having P. multocida infection. The gross and histopathological lesions can be helpful in the preliminary diagnosis of Pasteurellosis but needs to be supplemented by other immunodiagnostic tests. Moreover, IHC technique proved to be a specific, reliable, precise, and rapid technique to supplement these conventional methods of diagnosis for Pasteurellosis.

Localization of classical swine fever virus antigen in young piglets by immunohistochemistry

The present study investigated the diagnosis of classical swine fever in piglets of four to six months using gross lesions, histopathology and immunohistochemistry. Gross examination revealed hemorrhagic kidneys, lymph nodes and spleen along with button shaped ulcer in intestine. Histopathological examination revealed focal to diffuse haemorrhages in the red pulp of spleen with depletion of the lymphocytes and multiple ulcerative lesions with necrosis of the epithelial mucosa in large intestine. Immunohistochemically, the viral antigen was demonstrated in the bronchial epithelial cells, mononuclear cells in spleen, intestine and Purkinje cells of the brain.

Evaluation of lateral flow assay as a field test for investigation of brucellosis outbreak in an organized buffalo farm: a pilot study.

Aim: The aim was to evaluate lateral flow assay (LFA) as a field test for investigation of brucellosis outbreak in organized buffalo farm. Materials and Methods: A total of 153 serum samples were tested to detect the presence of brucella antibodies by LFA and three other serological tests i.e. rose bengal plate test (RBPT), protein G based indirect enzyme-linked immunoassay (iELISA), and competitive ELISA (cELISA). The performances of LFA and other serological tests were evaluated using OIE complaint cELISA as the gold standard. Results: Serological tests revealed 50% of the animals were seropositive for Brucella antibodies and correlated with clinical history of abortions, infertility, and productive failures. The newly developed assay showed 87.1% and 92.6% sensitivity and specificity, which was even higher than the specificity of RBPT. Conclusions: The investigation proved the potential usefulness of LFA for field diagnosis of brucellosis in the regions where laboratory facilities are limited.

Outbreaks of Anaplasmosis in Dairy Cattle in Punjab, India

Two severe outbreaks of bovine anapalsmosis caused by Anaplasma marginale were recorded in two districts (Ferozepur and Patiala) of Punjab state in the year 2016. Mortality of animals was recorded in two dairy cattle herd comprising of a total of 260 animals in Ferozepur (n=218) and Patiala (n=42) districts. There was history of purchase of animals at one farm. Out of 260 cattle at risk, 40 were critically ill and 9 died of disease with morbidity, mortality and case fatality rate of 15.38 %, 3.46 % and 22.50 % respectively. Fifteen blood samples were collected from diseased (n=11) and healthy animals (n=4) for haematological analysis, parasitological and polymerase chain reaction (PCR) based diagnosis. Clinical signs in infected animals included high temperature, icterus, anemia, anorexia and decreased milk production. Necropsy findings revealed splenomegaly and severe jaundice. Mild tick infestation was observed at both the farms. Ticks collected from both the outbreaks were identified as Rhipicephaus (Boophilus) microplus. Thin blood smears from infected animals were found positive for Anaplama marginale organisms & disease was further confirmed by molecular approach (PCR). Affected animals were successfully treated with tetracycline, haematinics and antipyretics. PCR was found to be more sensitive in detecting the disease especially in latent infections. Animal owners were advised to follow quarantine measures before mixing new animals in a herd and strategic acaricidal treatment for effective tick control.

Diagnosis of Newcastle disease in broiler by histopathology and immunohistochemistry

Newcastle disease (ND) is an OIE notifiable, highly contagious, generalized viral disease of poultry. It remains a constant threat to the poultry industry and is a limiting disease for poultry producers worldwide. The present study report a severe enteric form of ND virus infections in backyard poultry birds by using histopathology and immunohistochemistry. ND viral antigens were detected in the lesions of various organs. ND viral antigen were mainly localized in the cytoplasm and nuclei of necrotic cells of epithelium of proventriculus, gizzard and intestines, Kupffer cells and circulating monocytes in the liver, tracheal epithelial cells, bronchiolar and parabronchiolar epithelial cells and alveolar macrophages in the lungs. Thus, immunohistochemistry serve as rapid and reliable tools to study the tropism and distribution of ND viral antigen in the tissues of infected birds and hence its diagnosis.

Epidemiological and immunopathological studies on Porcine parvovirus infection in Punjab

Aim: The aim of this study was to get the first-hand knowledge about the seroprevalence of Porcine parvovirus (PPV) in Punjab and a diagnosis of PPV from abortion cases of swine using gross, histopathological, and immunohistopathological techniques to observe the tissue tropism of the virus strain. Materials and Methods: Tissue samples from the reproductive tract of pig (n=32), placental tissue (n=10), and aborted fetuses (n=18) were collected from Postmortem Hall of the Department of Veterinary Pathology, GADVASU, field outbreaks and from butcher houses in and around Ludhiana. These samples were processed for histopathological and immunohistochemical (IHC) studies. For seroprevalence study, 90 serum samples of different sex and age were collected from 15 swine farms of Punjab and were subjected to indirect enzyme linked immunosorbent assay using commercial kit. Results: Overall, seroprevalence of PPV was found to be 41.1%. Sex and age related difference in the prevalence was noted. In abortion cases grossly congested and emphysematous lungs, congested internal organs with fluid in abdominal cavity and congestion in brain, changes were noted in fetuses, while diffuse hemorrhages and edema was observed in placental tissue. Histopathologically, the most frequent fetal lesions in aborted fetuses were noted in lungs, liver, and brain. IHC staining revealed PPV antigens in sections of heart, liver, lung, spleen, brain, lymph node of fetuses, placenta, and uterus of sow. Gross, histopathological, and IHC examination of the samples confirmed 5 fetus, 2 placenta and 3 female reproductive samples positive for parvovirus infection. Conclusions: Seroprevalence results may serve as a support either in prevention or control of the disease. IHC is the sensitive technique for diagnosis of PPV associated with the reproductive tract of swine and was found to supplement the gross and histopathological alterations, respectively, associated with the disease.

Diagnosis and management of bovine babesiosis outbreaks in cattle in Punjab state.

Aim: The aim of the present study was to diagnose severe outbreaks of bovine babesiosis in Punjab state, in the year 2015 and to suggest control and preventive measures to animal owners. Materials and Methods: Mortality of animals was recorded in two cattle herd comprising a total of 465 cattle in Sangrur (n=125) and Faridkot (n=340) districts. There was a history of purchase of animals at one farm. 23 blood samples were collected from diseased (n=15) and healthy animals (n=8) for hematological analysis, parasitological, and polymerase chain reaction (PCR)-based diagnosis. Ticks were also collected from animals for identification. Results: Out of 465 cattle at risk, 28 were critically ill and 14 died of disease with morbidity, mortality, and case fatality rate of 6.02%, 3.01%, and 50.00%, respectively. Clinical signs and necropsy findings were suggestive of babesiosis. Ticks collected from both the outbreaks were identified as Rhipicephalus (Boophilus) microplus. Thin blood smears from infected animals (especially with clinical sign of hemoglobinuria) were found positive for Babesia bigemina organisms; however, molecular diagnosis (PCR) further confirmed the disease. Animals were successfully treated with diminazene aceturate, hematinics, and antipyretics. Conclusions: Two fatal outbreaks of babesiosis in cattle were diagnosed with application of conventional parasitological, hematological, and molecular diagnostic techniques. PCR was found to be far more sensitive in detecting the disease, especially in latent infections. Animal owners were advised to follow quarantine measures before mixing new animals in the herd and strategic acaricidal treatments for effective tick control.